Figure 5: CHEST XRAY WITH PULMONARY CONGESTION
DISCUSSION
Primary percutaneous intervention (pPCI) has revolutionized the treatment in ST-elevation myocardial infarction (STEMI) and tremendously decreased the rate of mechanical complications. In the pre-fibrinolytic period, the rate of mechanical complications was 6%, while it has been reduced to <0.5% in the revascularization era. In an analysis of 4 million hospitalized STEMI patients from 2003 to 2015, mechanical complications have been reported in only 0.27% of patients with PMR incidence as low as 0.05%.2
The optimal timing of papillary muscle rupture is 2 to 7 days post-myocardial infarction. Mortality was reported 50% within 24 hrs without surgical intervention. 82% of patients with first myocardial infarction were reported to have papillary muscle rupture.3,4
Echocardiography with Doppler is the cornerstone for the diagnosis of this fatal complication. The sensitivity of TTE to visualize the structural abnormalities has been estimated to be 65-85%, with transesophageal echo sensitivity approaching 92-100%.
The rupture of the posteromedial papillary muscle is 6 to 12 times more common than the anterolateral papillary muscle due to its single blood supply from the posterior descending artery of the dominant right coronary artery (RCA) or dominant left circumflex artery (LCX), causing inferior wall myocardial infarction (IWMI).5 Most cases of PMR occur after small areas of ischemia, usually less than 25% of left ventricular with poor collaterals, and is thought to be due to preserved ventricular function exhibiting increased shear stress to the ischemic papillary muscle.
Our patient did not have an audible murmur of severe mitral regurgitation, which could be explained by the rapid equalization of pressures within the left ventricle and left atrium.
This case was unusual as he had successful thrombolytic reperfusion of acute inferior infarction at presentation. Later he again developed in-hospital re-infarction leading to PMR. Whether it is related to covid 19 infections is unknown to us with a lack of strong evidence.
There have been reports of increased coronary artery thrombus burden in patients with STEMI in COVID 19 positive patients.6This is consistent with an increased frequency of thrombotic strokes, particularly in young people, during the pandemic. Alterations in the coagulation system, abnormal platelet function, or abnormal endothelial function have been postulated.7
Early diagnosis, prompt hemodynamic support to reduce afterload with appropriate medications as well as with devices like intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), and Tandem heart, and immediate surgical intervention are required to reduce morbidity and mortality due to papillary muscle rupture secondary to Acute myocardial infarction.8
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